In recent years, advancements in rock crusher controls have involved utilization of more complex electronics. However, this has also increased the concern for reducing the vibration experienced by electronic or other shake-sensitive components of such mobile rock crushers. Some designs have been improved by isolating the electronic control box or panel of the rock crusher from vibration. The high amplitude, low frequency vibrations generated by the crusher can cause problems with the electronic components inside the box. The fine wires mounting components inside the electronic devices can break due to fatigue and over time, can cause equipment shut-down conditions.
In the past, shock-absorbing mounts have been attempted to separate the control box from rigid structure on the mobile crusher. Because of the large amplitude of these vibrations, these mounts have been generally quite soft. While soft mounts can effectively reduce the vibration transmitted to the electric control box, they lead to instability on the highway as the control boxes may weigh around 1000 lbs or more with certain crusher designs. Having a 1000-lb package elevated above the ground and mounted on very soft mounts is less than optimal.
It is becoming common for crushing plant manufacturers to recommend that sensitive electronics be removed when the crusher is in operation. Recently, crusher manufacturers have employed a removable electronic control panel which is taken off the vehicle and placed on the adjacent surface of the ground. The ground acts to dampen the vibrations from the rock crusher and isolate the electronic control panel.
Common practice for many operators of crushing plants is to use an end loader to lift the electrical control panel or cabinet from a mounting position on the plant/vehicle and lower it to the ground. This often means the operator ties a chain, strap, cable, or other device to lifting eyes mounted to the top of the cabinet and the bucket of the loader. Once the panel is lifted from the mounting brackets on the plant, there are usually no guides to hold it in position (keep from twisting, etc). This can result in difficult handling and damage to the cabinet, wiring, or plant due to the tight clearances and “lack of finesse” associated with the loader controls. Because of these problems, some crusher operators resort to simply ignoring the recommendation to remove the panel from the plant during operation.
One improvement to the loader lift idea has been a special purpose crane boom built by James W. Bell Manufacturing of Cedar Rapids, Iowa. This device may hold two electrical cabinets side by side. A hydraulic cylinder extends and retracts to raise and lower the cabinet, but the swing toward and away from the plant is manual. It may employ a “loose” (chain, etc.) mount between the boom/arm and the cabinet to isolate vibration from the plant.
While removing the electronic control panel and placing it on the ground to enhance vibration isolation has been used successfully in the past, numerous problems exist with prior art removable electronic control boxes. The approach using a front end loader with a chain to lift the electronic control box off the vehicle and lower it to the ground has numerous drawbacks, including the need to have a front end loader available, as well as a skilled front end loader operator. While the James W. Bell unit has eliminated the need for a front end loader, it now requires a person to swing the electric box away from the vehicle. This involves pushing on the electrical box after it is lifted and is free to swing about. This step creates an opportunity for a personal injury or damage to the plant to occur by placing a person next to a 1000-lb elevated and swinging object. This design and others may require extra care during deployment to take up and let out extra electrical cabling which extends between the mobile rock crusher and the electronic control box.
Consequently, there exists a need for improved methods and systems for offloading an electrical control box from a mobile rock crusher, which simultaneously provides for increased safety and speed of downloading.